Class: Bispecific T-cell engager (BiTE®)
Mechanism of Action:
- Simultaneously binds CD19 on B cells and CD3 on T cells
- Redirects cytotoxic T cells to kill CD19+ B-lineage cells (including malignant B cells)
Indications
- Relapsed/refractory B-cell precursor Acute Lymphoblastic Leukemia (ALL) in adults and children
- Minimal residual disease (MRD)-positive B-ALL
- Under investigation for other CD19+ malignancies
Administration
- Continuous IV infusion via pump over 28 days (21–28 day cycle)
- Requires hospitalization during first 9 days (Cycle 1) due to risk of CRS and neurotoxicity
- Step-up dosing to reduce adverse effects:
- Cycle 1: 9 mcg/day (days 1–7) → 28 mcg/day (days 8–28)
Key Side Effects
- Cytokine Release Syndrome (CRS) – fever, hypotension, hypoxia
- Neurotoxicity – confusion, seizures, encephalopathy
- Cytopenias (neutropenia, thrombocytopenia)
- Infections
- Tumor lysis syndrome (TLS)
Monitoring
- Baseline: CBC, LFTs, infection screening, neurologic assessment
- During therapy:
Supportive Measures
- Premedicate with dexamethasone before each dose
- Interrupt or discontinue for grade ≥3 neurotoxicity or CRS
- Requires inpatient initiation (Cycle 1) in many protocols
Other Notes
- Only available as continuous infusion (hospital or home-based with pump)
- CD19 expression required on target cells
- No direct myelosuppressive chemotherapy component
- Immunogenicity is low, but hypersensitivity is possible